Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 309 for “"Radiated"”.
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Radiated noise from a three dimensional truss
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1995, and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1995.
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Active Control Of Noise Radiated From Personal Computers
… drives also contribute to the annoying noise radiated by personal computers, creating a need for the control of computer noise. Due to size constraints, the implementation of passive noise control techniques in PC is difficult. Alternatively, active noise control (ANC) may provide a compact …
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Control of Radiated Noise from Fluid-Loaded Stiffened Structures
… of BF waves and their contribution to the radiated sound power by utilising non-negative intensity (NNI) technique. Additionally, a passive control technique based on the acoustic black holes (ABHs) is developed to control vibroacoustic responses of fluid-loaded stiffened plates. This has …
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Radiated Noise Assessment of Shipboard Systems Using Vibration Analysis
… the predictive maintenance system to predict the radiated noise due to vibrations from the ship’s systems. First, a scientific survey to study the field yielded two plausible theoretical models that could help predict vibro-acoustic transmissions in complex systems - Finite Element Analysis and …
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Ultrasonic waves in solids radiated from an elliptically loaded source
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2000.
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Designed Reduction of Radiated Noise Characteristics from Two-Bladed General Aviation Propellers
<p>In recent years increased public awareness has made the reduction of environmental noise pollution a top priority for the aviation industry. Utilizing current technology, this study examines the reduction of noise generated by two bladed general aviation propellers, through design. The Aircraft …
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Effect of heating on sound radiated from a two-dimensional mixing layer
The effect of heating on sound radiated by instability waves in a two-dimensional mixing layer is studied. A linear stability theory coupled with linearized Euler calculations are used to compute the amplitude of the instability wave and its associated sound field. The linear stability analysis …
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Sound Radiated from Turbulent Flow over Two and Three-Dimensional Surface Discontinuities
Measurements have been performed to understand the sound source mechanism in turbulent boundary layer flow over two and three-dimensional surface discontinuities whose height is smaller than the incoming boundary layer thickness. The work was performed in two different types of boundary layers: a …
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Analytical investigation of active control of radiated inlet noise from turbofan engines
… of active noise control techniques for reducing radiated tonal inlet noise from turbofan engines. The analytical model consists of multiple control sources placed in the periphery of the engine inlet duct which inject anti-noise into the duct to destructively interfere with the sound field …
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Three-Bladed Propeller Design for the Reduction of General Aviation Radiated Noise Characteristics
… for predicting the aerodynamic performance and radiated noise characteristics for both the 2-bladed and 3-bladed propeller designs. Through blade design modifications and the use of conventional, as well as specifically designed natural-laminar-flow (NLF) airfoils, 3-bladed propeller designs …
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Characterization of the measurement uncertainty for the electromagnetic conducted and radiated emission test
… conditions apply for both conducted (CE) and radiated emission (RE). Other areas are now introducing regulations and it seems likely that the system will spread to encompass the whole world in the future. Currently, measurement of an equipment under test (EUT) shall cast a doubt when the …
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Prediction And Measurement Of Radiated Emissions Based On Empirical Time Domain Conducted Measurements
This thesis develops a novel method to predict radiated emissions measurements. The techniques used are based on standard Electromagnetic Compatibility (EMC) qualification test methods. The empirical data used to formulate the final results was restricted to pertinent data protocol waveforms …
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Source reconstructions for IC radiated emissions based on magnitude-only near-field scanning
<p>"In this dissertation, a source reconstruction method is proposed to model the emission behavior of an IC by using magnitude-only information during near-field scanning. The phase-retrieval is accomplished during the back-forth iterations between two scanning planes of different heights. The …
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Active control of radiated noise from a cylindrical shell using external piezoelectric panels
… methodologies are developed for the reduction of radiated noise from a thick-walled cylindrical shell using external piezoelectric panels. The proposed approach is to cover the shell's outer surface with curved active composite panels, and to reduce the radiated noise by controlling the motion of …
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Active Minimization of Acoustic Energy Density to Attenuate Radiated Noise from a Diesel Generator
… overall sound pressure level (SPL) reduction of radiated noise. The target levels for overall SPL reduction were at least 2 dBA. The control algorithms used in this research were based on a filtered-x LMS adaptive algorithm, which minimizes energy density (ED). Both feedforward and feedback …
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Attenuation of Low Frequency Structurally Radiated Noise With an Array of Weak Radiating Cells
… cell is proposed to reduce the low frequency radiated noise from structures. The cell consists of two coupled surfaces such that, when placed on a vibrating structure, the responses of the two surfaces are nearly out-of-phase and of equal strength over a wide frequency range. This structure …
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Measurement and application of near-field scan data: prediction of currents, radiated emissions, and probe characteristics
"This dissertation examines the application of near field measurement techniques and analysis originally developed for the analysis of antennas to the specific case of electromagnetic compatibility"--Abstract, page iv.
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